San Francisco, Jul 29 (IANS): Microblogging site Twitter has confirmed that it is raising the price of its premium subscription service, Twitter Blue, from $2.99 to $4.99 monthly -- a 66 per cent increase.

In an email sent to Twitter Blue subscribers, the company said that the price increase is only for new subscribers for now; existing subscribers will not be charged the higher rate until October, reports CNET.

"At launch, we felt strongly about keeping the cost of the subscription as low as possible while we tested, learned and gathered feedback," a Twitter spokesperson was quoted as saying in a statement.

"We have since refined the vision for this product, conducted significant research, introduced new enhancements with more in development, and as such, we are updating pricing," the spokesperson added.

The premium service allows subscribers to pay for features such as the ability to undo a tweet and read ad-free news articles.

The platform said the price increase will go toward developing new features and improving on existing ones in an effort to support journalism.

Twitter Blue gives users a 30-second undo tweet window that allows them to make revisions to their tweets before it is posted on Twitter.

It also allows users to customise their experience with themes and icons and organise tweets in a bookmark folder.